Genetically engineered bacterium for expressing carboxypeptidase G2 as well as preparation method and application of genetically engineered bacterium

The invention discloses a genetically engineered bacterium for expressing carboxypeptidase G2 as well as a preparation method and an application of the genetically engineered bacterium. The genetically engineered bacterium is a genetically engineered bacterium for simultaneously expressing a SUMO protein label and a carboxypeptidase G2 gene in Escherichia coli, and an SMT3 gene for expressing theSUMO protein label is positioned at the upstream of a CPG2 gene for expressing the carboxypeptidase G2. When the genetically engineered bacterium is used for preparing CPG2, the genetically engineeredbacterium has the characteristics of high expression efficiency, large expression quantity, low cost, easiness in operation and the like, and the expressed recombinant CPG2 protein is high in purity(up to 99.1%) and high in activity (up to 1792U/mg) and has a good industrial application prospect. 本发明公开了一种表达羧肽酶G2的基因工程菌及其制备方法和应用。所述的基因工程菌为大肠杆菌(Escherichia coli)中同时表达SUMO蛋白标签和羧肽酶G2基因的基因工程菌，表达所述SUMO蛋白标签的SMT3基因位于表达所述羧肽酶G2的CPG2基因